import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

class Demo3_1_1{
    public static void main(String[] args) {
        List<Integer> list = Arrays.asList(1, 2);
        System.out.println("--------------- map 前");
        System.out.println(list);
        System.out.println("--------------- map 后");
        List<String> mappedList = list.stream().map(x -> x + 100)
                .map(x -> x + "").collect(Collectors.toList());
        System.out.println(mappedList);
    }
}